A fuel cell is a device which uses an electrochemical reaction to convert chemical energy stored in a fuel such as hydrogen or methane into electrical energy. In general, fuel cells include an anode to catalytically react with the fuel and a cathode in fluid communication with an oxidant such as air. The anode and cathode are disposed on opposing sides of an electrolyte material which conducts electrically charged ions therebetween. The electrolyte material and the design of the fuel cell determine the type and performance of the fuel cell. For example Molten Carbonate Fuel Cells (MCFC), which operate at approximately 650° C., typically include an electrolyte which is a molten liquid during operation.
Typical MCFCs include a first conduit disposed adjacent to an anode, a second conduit disposed adjacent to a cathode; and an electrolyte matrix disposed between the anode and the cathode. The first conduit channels fuel to the anode and the second conduit channels an oxidant such as air to the cathode. The first and second conduits can include current collectors and flow distribution members therein.
In a typical MCFC, the cathode is made of a lithiated NiO and the electrolyte includes a carbonate material (e.g., alkali carbonate mixture), for example a material including CO3−2 that is in a liquid form during operation. During operation, nickel ions Ni+2 from the NiO cathode can dissolve and re-precipitate as electrically conductive metallic nickel particles in matrix pores and also preferentially in defects such as micro-cracks present within the electrolyte matrix. The nickel particles can join to one another and can cause an electrical short circuit between the cathode and a portion of the first conduit adjacent to the anode. Such electrical short circuits can degrade performance of the MCFC.